L3: Functional divisions of the nervous system and autonomic Nervous System

Question 1

What provides most of the control function over our bodies?

Answer 1

The nervous system

Question 2

What does the nervous system do?

Answer 2

It receives thousands of information from different sensory organs and analysis all of them to determine the response to be made by the body.

Question 3

What is the neuron?

Answer 3

It is the structural or anatomical unit of the nervous system.

Question 4

What is the neuron formed from?

Answer 4

It is formed from the cell body and cell processes.

Question 5

What is the function of the cell body of the neuron?

Answer 5

Controls the activity of the whole neuron.

Question 6

What are the processes of the neuron?

Answer 6

Axon: Single long process - the conducting part - conducts impulses away from the cell body

Dendrites: Multiple short processes that inc. the surface area of the cell body - the receptive part - conduct impulses towards the cell body

Question 7

Near the termination of the axon, what does it join?

Answer 7

• Muscle—-> neuro-muscular junction
• Gland——> neuro-epithelial junction
• Another neuron—-> neuro-neural junction

Question 8

What are the types of neurons?

Answer 8

1. Afferent=sensory: carries impulses from receptors to CNS.
2. Efferent=motor: carries impulses from CNS to effector organs like muscles
3. Interneurons=associative: located inside CNS, Act as a link between neurons, 99% of nerve cells.

Question 9

What is reflex action?

Answer 9

Reflex action is the involuntary (programmed) response of a part of the body to a stimulus.

Question 10

How is reflex action carried out?

Answer 10

• Reflex action is carried out through a pathway called the reflex arc.

Question 11

What is the functional or physiological unit of the nervous system?

Answer 11

Reflex action

Question 12

What are the components of the reflex pathway?

Answer 12

1. Receptors.
2. Afferent (sensory).
3. Center (in CNS).
4. Efferent (motor).
5. Effectors (muscles or glands).

Question 13

What are the divisions of the nervous system?

Answer 13

• CNS

- PNS

Question 14

What is the definition of the central nervous system?

Answer 14

-It is the part of the nervous system which is protected by bone (skull and vertebral column).

Question 15

What are the parts of the CNS?

Answer 15

-It is consists of the brain and spinal cord.

A) Brain, which has 3 major subdivisions:

1-Cerebrum (2 cerebral hemispheres) which consists of:

a) Cerebral cortex.
b) Subcortical centers: thalamus, hypothalamus, and basal ganglia.

2-Brain stem: consists of 3 regions: midbrain, pons, and medulla oblongata.

3-Cerebellum.

B)Spinal cord: It is subdivided into 31 segments into the following regions:

8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

• Each spinal segment gives a pair of spinal nerves on both sides.

Question 16

What is the function of the peripheral nervous system?

Answer 16

The peripheral nervous system provides communication between the CNS and other tissues via nerves (PNS).

Question 17

What are the divisions of the PNS?

Answer 17

They are classified anatomically (cranial and spinal) and physiologically (somatic and autonomic)

Question 18

What are the divisions of the PNS according to anatomical classification?

Answer 18

1- 12 pairs of cranial nerves.

2- 31 pairs of spinal nerves.

Question 19

Cranial nerves

Answer 19

• All of them (12 pairs) arise from the brain & they include:

I - OLFACTORY - SMELL (CEREBRUM)

II - OPTIC - VISION (CEREBRUM)

III - OCULOMOTOR - MOVING THE EYEBALL (MIDBRAIN)

IV - TROCHLEAR - MOVING THE EYEBALL (MIDBRAIN)

V - TRIGEMINAL - SENSORY TO FACE (PONS)

VI - ABDUCENT - MOVING THE EYEBALL (PONS)

VII - FACIAL NERVE - MOVING FACIAL MUSCLES (PONS)

VIII - AUDITORY - HEARING (PONS)

IX - GLOSSOPHARYNGEAL - TASTE SENSATION FROM TONGUE AND PHARYNX AND SECRETORY TO SALIVARY GLANDS (MEDULLA OBLONGATA)

X - VAGUS - SENSORY AND MOTOR TO MUSCLES OF THORATC AND ABDOMINAL VISCERA (MEDULLA OBLONGATA)

XI - ACCESSORY - MOVING MUSCLES OF THE BACK OF THE NECK (MEDULLA OBLONGATA)

XII - HYPOGLOSSAL - MOVING THE TONGUE (MEDULLA OBLONGATA)

Question 20

What are the purely sensory cranial nerves?

Answer 20

I - II - VIII Fiat “128”

Question 21

What are the purely motor cranial nerves?

Answer 21

III - IV - VI “346”

Question 22

What are the mixed cranial nerves?

Answer 22

Anything except 128 and 346

Question 23

Spinal nerves

Answer 23

• they are 31 pairs
• These are attached to the spinal cord.
• Each spinal nerve arises from the sides of the spinal cord by two roots: dorsal and ventral.
• All spinal nerves are mixed nerves (sensory and motor).

Question 24

What is the peripheral nervous system classified into physiologically?

Answer 24

Somatic and autonomic

Question 25

Somatic nervous system

Answer 25

Voluntary - Connected With (skin, Skeletal muscles, tendons, bones, and joints)

Question 26

Autonomic nervous system

Answer 26

Involuntary - Connected With (Smooth muscles, glands, and cardiac muscle).

Question 27

What is the origin of the sympathetic NS?

Answer 27

• Originates from LHCs of all thoracic and upper 3 lumbar segments of the spinal cord.

Question 28

What is the origin of the parasympathetic NS?

Answer 28

• Cranial and sacral
• Cranial part:
   arises from cranial nerves: C III, VII, IX, and X (1973)

2- Sacral part:
 Arises from 2nd, 3rd, and 4th sacral segments of the spinal cord, their fibers unite to form the pelvic nerve.